1. Field of the Invention
The present invention relates to an air sterilization filter to be provided in a passage for evacuating air from biologically contaminated space, or feeding air into a clean space where biological work is carried out, such as a containment laboratory in the biotechnological field and the like.
2. Related Art Statement
A known air filter of this kind is the so-called HEPA filter, i.e., high efficiency particulate air filter, which can physically collect fine dust particles and microorganisms, such as bacteria, virus, etc. which are suspended in the air and have particle size diameter of at least 0.3 .mu.m, with a filtration efficiency of 99.97% or more, only by passing air through the microporous filter.
Accordingly, with conventional HEPA filters as described above, the collection of dust particles, microorganisms, such as bacteria, virus, etc, suspending in the air is not always effected with 100% certainity, entailing possible leakages, even through they may be very little, and further a phenomenon can occur such that particles once collected by the filter are dispersed again.